The present invention relates to dishwashing compositions comprising a alkylarylsulfonate surfactant system containing a mixture of isomers of crystallinity-disrupted, preferably branched, alkylarylsulfonate surfactants and optionally one or more noncrystallinity-disrupted alkylarylsulfonate surfactants.
Typical commercial hand dishwashing compositions incorporate divalent ions (Mg, Ca) to ensure adequate grease performance in soft water. However, the presence of divalent ions in formulas containing anionic, nonionic, or additional surfactants (e.g., amine oxide, alkyl ethoxylate, LAS, alkanoyl glucose amide, alkyl betaines) leads to slower rates of product mixing with water (and hence poor flash foam), poor rinsing, and poor low temperature stability properties. Moreover, preparation of stable dishwashing detergents containing Ca/Mg is very difficult due to the precipitation issues associated with Ca and Mg as pH increases. Consequently, there remains the need for a detergent composition suitable for hand dishwashing, which is stable at low temperatures, and additionally can provide grease removal and tough food cleaning benefits, in hard water and at pH""s, typically pH 9 or lower, where a conventional Ca/Mg system would be unstable and not provide grease removal and tough food cleaning benefits.
U.S. Pat. No. 5,026,933; U.S. Pat. No. 4,990,718; U.S. Pat. No. 4,301,316; U.S. Pat. No. 4,301,317; U.S. Pat. No. 4,855,527; U.S. Pat. No. 4,870,038; U.S. Pat. No. 2,477,382; EP 466,558, Jan. 15, 1992; EP 469,940, Feb. 5, 1992; FR 2,697,246, Apr. 29, 1994; SU 793,972, Jan. 7, 1981; U.S. Pat. No. 2,564,072; U.S. Pat. No. 3,196,174; U.S. Pat. No. 3,238,249; U.S. Pat. No. 3,355,484; U.S. Pat. No. 3,442,964; U.S. Pat. No. 3,492,364; U.S. Pat. No. 4,959,491; WO 88/07030, Sep. 25, 1990; U.S. Pat. No. 4,962,256, U.S. Pat. No. 5,196,624; U.S. Pat. No. 5,196,625; EP 364,012 B, Feb. 15, 1990; U.S. Pat. No. 3,312,745; U.S. Pat. No. 3,341,614; U.S. Pat. No. 3,442,965; U.S. Pat. No. 3,674,885; U.S. Pat. No. 4,447,664; U.S. Pat. No. 4,533,651; U.S. Pat. No. 4,587,374; U.S. Pat. No. 4,996,386; U.S. Pat. No. 5,210,060; U.S. Pat. No. 5,510,306; WO 95/17961, Jul. 6, 1995; WO 95/18084; U.S. Pat. No. 5,510,306; U.S. Pat. Nos. 5,087,788; 4,301,316; 4,301,317; 4,855,527; 4,870,038; 5,026,933; 5,625,105 and 4,973,788. The manufacture of alkylbenzenesulfonate surfactants has recently been reviewed. See Vol. 56 in xe2x80x9cSurfactant Sciencexe2x80x9d series, Marcel Dekker, New York, 1996, including in particular Chapter 2 entitled xe2x80x9cAlkylarylsulfonates: History, Manufacture, Analysis and Environmental Propertiesxe2x80x9d, pages 39-108 which includes 297 literature references. Documents referenced herein are incorporated in their entirety.
It has now been surprisingly found that when an alkylarylsulfonate surfactant system includes two or more isomers of crystallinity-disrupted alkylarylsulfonate surfactants, optionally containing also one or more noncrystallinity-disrupted alkylarylsulfonate surfactants, there is a surprising increase in performance over alkylarylsulfonate surfactant system which do not include the crystallinity-disrupted alkylarylsulfonate surfactant isomers.
The present invention has numerous advantages beyond one or more of the aspects identified hereinabove, including but not limited to: superior cold-water solubility, for example for cold water cleaning; superior hardness tolerance; and excellent detergency. Further, the invention is expected to provide improved removal of lipid or greasy soils. The development offers substantial expected improvements in ease of manufacture of relatively high 2-phenyl sulfonate compositions, improvements also in the ease of making and quality of the resulting formulations; and attractive economic advantages.
The present invention is based on an unexpected discovery that there exist, in the middle ground between the old, highly branched, nonbiodegradable alkylbenzenesulfonates and the new linear types, certain alkylbenzenesulfonates which are both more highly performing than the latter and more biodegradable than the former.
The new alkylbenzenesulfonates are readily accessible by several of the many of known alkylbenzenesulfonate manufacturing processes. For example, the use of certain dealuminized mordenites permits their convenient manufacture.
In accordance with the present invention, a novel hand dishwashing composition is provided. This novel hand dishwashing composition comprises
a) about 0.1% to about 99.90% by weight of said composition of an alkylarylsulfonate surfactant system comprising from about 10% to about 100% by weight of said surfactant system of two or more crystallinity-disrupted alkylarylsulfonate surfactants of formula
(Bxe2x80x94Arxe2x80x94D)a(Mq+)b
wherein D is SO3-, M is a cation or cation mixture, q is the valence of said cation, a and b are numbers selected such that said composition is electroneutral; Ar is selected from benzene, toluene, and combinations thereof; and B comprises the sum of at least one primary hydrocarbyl moiety containing from 5 to 20 carbon atoms, preferably 7 to 16, more preferably 9-15, most preferably 10-14 carbon atoms and one or more crystallinity-disrupting moieties wherein said crystallinity-disrupting moieties interrupt or branch from said hydrocarbyl moiety; and wherein said alkylarylsulfonate surfactant system has crystallinity disruption to the extent that its Sodium Critical Solubility Temperature, as measured by the CST Test, is no more than about 40xc2x0 C. and
xe2x80x83wherein further said alkylarylsulfonate surfactant system has at least one of the following properties:
percentage biodegradation, as measured by the modified SCAS test, that exceeds tetrapropylene benzene sulfonate; and
weight ratio of nonquaternary to quaternary carbon atoms in B of at least about 5:1 (preferably at least about 10:1; more preferably at least about 100:1); and
b) from about 0.00001% to about 99.90% by weight of said composition of a conventional hand dishwashing adjunct;
c) from about 0.01% to about 7% by weight of composition of a divalent ion selected from the group consisting of magnesian, calcium and mixtures thereof.
The composition will preferably contain at least about 0.1%, more preferably at least about 0.5%, even more preferably, still at least about 1% by weight of said composition of the surfactant system. The cleaning composition will also preferably contain no more than about 80%, more preferably no more than about 60%, even more preferably, still no more than about 40% by weight of said composition of the surfactant system.
The surfactant system will preferably contain at least about 15%, more preferably at least about 30%, even more preferably, still at least about 40% by weight of said surfactant system of two or more crystallinity disrupted alkyarylsulfonate surfactants. The surfactant system will also preferably contain no more than about 100%, more preferably no more than about 90%, even more preferably, still no more than about 80% by weight of said surfactant system of two or more crystallinity disrupted alkyarylsulfonate surfactants.
Accordingly, it is an aspect of the present invention to provide novel cleaning compositions. These, and other, aspects, features and advantages will be clear from the following detailed description and the appended claims.
All percentages, ratios and proportions herein are by weight of ingredients used to prepare the finished compositions unless otherwise specified. All temperatures are in degrees Celsius (xc2x0 C.) unless otherwise specified. All documents cited herein are, in relevant part, incorporated herein by reference.